This invention relates to a method wherein the components adjacent the top and bottom of a scroll compressor are all aligned with regard to a common reference such that total alignment of the components can be more easily and accurately achieved.
Scroll compressors are becoming widely utilized in refrigerant compression applications. In a scroll compressor, first and second scroll members each include a base and a generally spiral wrap extending from the base. The wraps interfit to define compression chambers. A shaft is operably connected to one of the scroll members to cause that scroll member to orbit relative to the other. As the two scroll members orbit, compression chambers defined between the wraps of the two scroll members decrease in volume, compressing an entrapped refrigerant.
Historically, scroll compressors are mounted in a sealed housing. The housing includes a center shell and upper and lower end caps. The shaft which drives the orbiting scroll member is typically driven by an electric motor mounted within the center shell. The shaft extends along a rotational axis, and is operably connected to the orbiting scroll to cause orbiting movement of the orbiting scroll. Typically, the shaft is mounted in bearings adjacent upper and lower positions. The upper bearing is mounted within a crankcase, which supports the orbiting scroll member. The lower bearing is typically on an opposed side of the motor from the scroll members. Historically, a bearing support has extended radially inwardly from the center shell to support the lower end of the bearing.
More recently it has been proposed to mount the lower bearing in the scroll compressor on the lower end cap. Thus, in prior U.S. patent application Ser. No. 09/376,915, filed Aug. 18, 1999, U.S. Pat. No. 6,247,909 and entitled xe2x80x9cBEARING ASSEMBLY FOR SEALED COMPRESSORxe2x80x9d, and further in a co-pending application entitled xe2x80x9cLOWER END CAP FOR SCROLL COMPRESSORxe2x80x9d filed on Jun. 1, 2001 and assigned Ser. No. 09/872,972, U.S. Pat. No. 6,560,868, lower end cap structure for mounting a bearing has been disclosed.
Further, it has recently been proposed to force fit the crankcase into the center shell such that the position of the crankcase is ideally located relative to the center shell. Such structure has been disclosed in co-pending application Ser. No. 09/176,576, filed Oct. 21, 1998 and entitled xe2x80x9cFORCE-FIT SCROLL COMPRESSOR ASSEMBLYxe2x80x9d and now assigned U.S. Pat. No. 6,193,484.
However, the two ideas have never been proposed to be combined.
In the disclosed embodiment of this invention, the center shell is utilized as a point of reference to ideally position the lower bearing through the mount of a lower end cap, and the crankcase both at a location ideally determined and positioned by the common reference. In a preferred embodiment, the common reference is provided by the center shell. The center shell is machined to have carefully controlled end surfaces that are both perpendicular to the center axis of the center shell, and which are ideally close to being cylindrical. The initial shell formation can be slightly out of round (i.e., on the order of 1.0 mm), as it will be brought to complete roundness by the computer cut surfaces of both the crankcase and the lower end cap, and as will be explained below.
The lower end cap is machined such that it has mount surfaces which are both perpendicular to the lower bearing bore and a set radial spacing away from the axis of the lower bearing. When this lower end cap is mounted within this center shell, the bearing is thus ideally located relative to the center axis of the center shell.
In a further embodiment, the unshaped structure which provides the outer surface for machining to ensure the lower bearing bore is true, is provided as a separate part welded to the lower shell. This simplifies the formulation of the lower shell blank.
Further, the crankcase is machined to have an idealized outer cylindrical surface, and a flat end face which abuts the end face of the center shell. When this crankcase is mounted in this center shell along with the lower end cap, it is assured that the crankcase and the lower end cap are both mounted at a proper orientation relative to each other. Since both the end cap and the crankcase are separately machined on their own to ensure that the axis of the bearing for the shaft that they each carry are true to the outer periphery of the individual component, it is also ensured that the two bearings are thus ideally located relative to each other. Once these two bearing mounts for the shaft are ideally determined, the other components of the scroll compressor come together easily and at assured aligned position.
Thus, the present invention provides a simplified method of ideally locating components within a scroll compressor such that it is assured they are properly located.
These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.